There has recently been development of semiconductor storage devices, e.g. flash memory cards which are nonvolatile semiconductor storage media. Such semiconductor storage devices are in widespread use as external storage devices of information equipment such as digital cameras, which are host equipment. The increase in volume of data to be handled by the host equipment has increased the capacity and density of a flash memory.
For the flash memory card, there is considered an approach to increase the speed of writing data into the flash memory. However, there is a problem of increased current consumption of the flash memory card.